This invention relates to improvements in commercial wind generators in use and under test. Present systems use a supporting rigid tower and very large wind turbine blades. The two major cost items are the blades and the supporting tower. Also, the present wind generators are fixed in location and elevation which limits the wind velocity and output on an annual basis. Locations are usually selected for high annual wind speeds, but the load factor is very low at the optimum wind speed.
Present large units are limited for use in high speed winds above the design level. They are usually designed to shut down at high wind speeds to prevent damage to the large turbine blade.
The new method for generating wind energy is to suspend small conventional wind generators in the air by a cable and to raise and lower the wind generators to the best elevation for maximum wind speed and electrical output.
A survey of wind speed with elevation revealed that wind speeds are 3 to 4 times higher above ground level and have a higher load factor. The electrical energy generated is a function of the cube of wind speed.
Typical data obtained from the National Weather Service, which makes high altitude wind velocity measurements at numerous locations across the country, several times a day, are as follows.
______________________________________ Elevation - Meters Wind Speed - Knots ______________________________________ 0 14 296 31 853 41 2177 47 3604 58 3808 65 ______________________________________
The new system has numerous small airplane-type propellers for driving conventional electrical generators which are both reasonable in cost. The propeller and generator rotors are mounted on the same shaft, rotating at the speed of wind. Generators may be high frequency aircraft type, DC type, or induction generators. The units are connected in parallel by cables to ground equipment which changes the output to a 60 HZ fixed voltage for supplying an existing electrical utility grid.
The small propellers are suitable for wind speeds of several hundred miles per hour. The weights of the generators and equipment are reduced by using non-metallic housings and materials. The kite structure has materials used in airplanes for light weight and high strength.
The high tower cost is replaced by high strength anchoring cables and the means to elevate and suspend the wind generator at high altitudes. The wind generators are held in the air by a structure similar to the principle of a kite. The wind, along with the high strength anchor cables, tend to hold the kite in place. To lift the generator into place, a helicopter-type rotor blade and a balloon are attached to the structure of the wind generator kite. They are controlled from the ground through control wires. Once airborne, the wind generator kite will be supported by the wind and hot gas balloon.
A single high strength anchoring cable is used for holding the wind generator kite. Control auxiliary power cables, electrical generator cables, and a natural gas pipe are attached to the anchoring cable for the electrical generators, helicopter-type engine, and hot gas balloon. A multiple large reel winch, power driven, raises and lowers the wind generator kite. The power cables, control cables, and gas pipes are on separate reels. They are attached to the anchoring cables on raising and removed when the kite is lowered.
The system has the advantage of being maneuverable to new locations on the ground and for making adjustments vertically for maximum wind velocity and electrical output. The wind generator kite has a tail rudder for orienting the kite to wind direction. The anchoring cable has a swivel which permits rotation of the kite.